Implantable medical device including welded septum assemblies

ABSTRACT

An implantable medical device includes a header body and a septum assembly. The header body includes a first welding surface and a septum bore extending inwardly from an outer surface to an inner cavity. The septum assembly is at least partially disposed within the septum bore of the header assembly and includes a septum configured to allow insertion of a tool through the septum into the inner cavity and to otherwise provide a seal. The septum assembly further includes a retainer within which at least a portion of the septum is retained. The retainer includes a welding feature coupled to the retainer body, the welding feature providing a second welding surface. The retainer is coupled to the header body by welding the first welding surface to the second welding surface.

FIELD OF THE INVENTION

Aspects of the present invention relate to medical apparatus. Morespecifically, the present invention relates to an implantable electronicdevice including a header and septum assemblies to enable access to aninternal volume of the header, the septum assemblies being welded to theheader.

BACKGROUND OF THE INVENTION

Implantable electronic devices (IEDs) include implantable pulsegenerators (IPGs) such as pacemakers and implantable cardioverterdefibrillators (ICDs), which are used in the treatment of cardiacconditions, and neuromodulators or neurostimulators, which are used inchronic pain management or the actuation and control of other bodysystems. These IPGs commonly include a housing, feedthrus, and aconnector assembly that is enclosed in a header. Electrical stimulationoriginating in the housing is led to the connector assembly throughfeedthrus. The connector assembly serves to transmit electrical signalsout of the IPG and to a lead electrically connected to the connectorassembly, the lead transmitting electrical signals between the IPG andpatient tissue.

A header of an IPG encloses the connector assembly, which has manyinternal electrically conductive components such as, for example, wires,ribbon, antennas, blocks, rings, etc. The connector assembly furtherincludes one or more connector blocks into which terminal ends of leadsmay be inserted. In certain IPGs, the connector blocks or adjacentstructures may include setscrews that may be tightened after insertionof a terminal lead end to fix the terminal lead end.

The setscrews may be disposed within an internal cavity of the header. Aseal may be provided to prevent communication of electrical signals aswell as bodily or other fluids into the internal cavity of the header;however, such a seal must permit access to the set screw in the eventthe leads of the IPG are to be disconnected from the header.

It is with the foregoing in mind that the following concepts wereconceived and developed.

SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, an implantable medical deviceincluding a header body and a septum assembly is provided. The headerbody includes a first welding surface, an outer surface, an innercavity, and a septum bore extending inwardly from the outer surface tothe inner cavity. The septum assembly is at least partially disposedwithin the septum bore of the header assembly and includes a septumconfigured to allow insertion of a tool through the septum into theinner cavity and to provide a seal when the tool is not inserted throughthe septum. The septum assembly further includes a retainer having aretainer body within which at least a portion of the septum is retained.The retainer further includes a welding feature coupled to the retainerbody, the welding feature providing a second welding surface. Theretainer is coupled to the header body by ultrasonically welding thefirst welding surface to the second welding surface.

In one implementation, the welding feature is a flange extendinglaterally from the retainer body.

The first welding surface may, in certain implementations, be a portionof the outer surface of the header body. In another implementation, thefirst welding surface may be disposed within the septum bore. In suchimplementations, the septum bore may include a counter bore and thefirst welding surface may be at least a portion of a bottom surface ofthe counter bore.

In some implementations, prior to being welded, at least one of thefirst welding surface and the second welding surface includes an energydirector extending therefrom such that when welded, the energy directorat least partially forms a joint between the retainer and the headerbody. In such implementations, the energy director may be a protrusionextending from the at least one of the first welding surface and thesecond welding surface. Alternatively, the energy director may be atextured portion of the at least one of the first welding surface andthe second welding surface.

In other implementations, the first welding surface and the secondwelding surface may be formed from respective transparent thermoplasticmaterials, such as, thermoplastic polyether polyurethane.

In still other implementations, the header body may further include aninsert that includes the first welding surface and at least partiallydefines the septum bore.

In yet other implementations, the septum may be disposed entirely belowthe outer surface of the header body. A set screw may also be disposedwithin the inner cavity of the header body.

In another implementation, the implantable medical device may furtherinclude a sealing element disposed between the retainer and the headerbody, the sealing element providing a fluid seal between the retainerand the header body.

In another aspect of the present disclosure, a method of manufacturingan implantable electronic device (IED) is provided. The method includesdisposing a septum assembly in a bore of a header body of the IED, theseptum assembly including a septum and a retainer, the septum assemblydisposed in the bore such that the septum is at least partially disposedwithin the bore and the retainer abuts a surface of the header body. Themethod further includes ultrasonically welding the retainer to theheader body.

In one implementation, the retainer includes a body and a flangeextending from the body such that when the septum assembly is disposedin the bore. The flange abuts an outer surface of the header body whenthe septum assembly is disposed within the bore and ultrasonicallywelding the retainer to the header body includes ultrasonically weldingthe flange to the outer surface.

In another implementation, the bore includes a counter bore having abottom surface and ultrasonically welding the retainer to the headerbody includes ultrasonically welding the retainer to the bottom surfaceof the counter bore.

In yet another implementation, the method includes disposing a sealingelement between the retainer and the header body prior to ultrasonicallywelding the retainer to the header body. In such implementations, thesealing element may be an elastomeric ring or may be a portion of theseptum.

In still another implementation, the retainer includes an energydirector, and ultrasonically welding the retainer to the header bodyresults in the energy director melting to join the retainer to theheader body.

In another aspect of the present disclosure, another implantable medicaldevice including a header body and a septum assembly is provided. Theheader body includes a first welding surface, an outer surface, an innercavity, and a septum bore extending inwardly from the outer surface tothe inner cavity. The septum assembly is at least partially disposedwithin the septum bore of the header assembly and includes a septumconfigured to allow insertion of a tool through the septum into theinner cavity and to provide a seal when the tool is not inserted throughthe septum. The septum assembly further includes a retainer having aretainer body within which at least a portion of the septum is retained.The retainer further includes a welding feature coupled to the retainerbody, the welding feature providing a second welding surface. Theretainer is coupled to the header body by laser welding the firstwelding surface to the second welding surface.

In one implementation, the welding feature is a flange extendinglaterally from the retainer body.

The first welding surface may, in certain implementations, be a portionof the outer surface of the header body. In another implementation, thefirst welding surface may be disposed within the septum bore. In suchimplementations, the septum bore may include a counter bore and thefirst welding surface may be at least a portion of a bottom surface ofthe counter bore.

In other implementations, the first welding surface and the secondwelding surface may be formed from respective transparent thermoplasticmaterials, such as, thermoplastic polyether polyurethane.

In still other implementations, the header body may further include aninsert that includes the first welding surface and at least partiallydefines the septum bore.

In yet other implementations, the septum may be disposed entirely belowthe outer surface of the header body. A set screw may also be disposedwithin the inner cavity of the header body.

In another implementation, the implantable medical device may furtherinclude a sealing element disposed between the retainer and the headerbody, the sealing element providing a fluid seal between the retainerand the header body.

In another aspect of the present disclosure, a method of manufacturingan implantable electronic device (IED) is provided. The method includesdisposing a septum assembly in a bore of a header body of the IED, theseptum assembly including a septum and a retainer, the septum assemblydisposed in the bore such that the septum is at least partially disposedwithin the bore and the retainer abuts a surface of the header body. Themethod further includes laser welding the retainer to the header body atan interface between the retainer and the header body by passing a laserthrough the retainer to the interface.

In one implementation, the retainer includes a body and a flangeextending from the body such that when the septum assembly is disposedin the bore, and the laser is passed through the flange.

In another implementation, the bore includes a counter bore having abottom surface and the interface is between the retainer and the bottomsurface of the counter bore.

In yet another implementation, the method further includes, prior tolaser welding the retainer to the header body, disposing a sealingelement between the retainer and the header body. The sealing elementmay be, for example, one of an elastomeric ring and a portion of theseptum.

In still another implementation, the method further includes, prior tolaser welding the retainer to the header body, applying pressure to theseptum assembly such that the septum assembly is forced into the bore.In one such implementation, the pressure is applied by a plate and thelaser is further passed through the plate.

In another implementation laser welding the retainer to the header bodyincludes welding the retainer to the header body using a fiber laser. Incertain implementations, the fiber laser has a wavelength ofapproximately two-microns.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a proximal end portion (i.e., leadconnector end) of a transvenous bipolar pacing lead;

FIG. 2 is an isometric view of a cardiac pacemaker/defibrillator unit(i.e., implantable pulse generator (IPG)) incorporating connectorjunctions or terminals for communication with one or more electrodes;

FIG. 3 is an isometric view of a representative header;

FIGS. 4A and 4B are opposite isometric views of a representativeconnector assembly used with the header of FIG. 3 to form a headerconnector assembly;

FIG. 5 is a cross-sectional view of a header including septumassemblies;

FIG. 6 is a detailed cross-sectional view of the septum assembly of FIG.5;

FIG. 7 is an isometric view of the septum assembly of FIG. 6;

FIG. 8 is an isometric cross-sectional view of the septum assembly ofFIG. 6;

FIG. 9 is an isometric cross-sectional view of a retainer of the septumassembly of FIG. 6;

FIG. 10 is an isometric cross-sectional view of an alternative retainerfor use in the septum assembly of FIG. 6 including a single triangularenergy director;

FIG. 11 is a detailed cross-sectional view of an alternative septumassembly bore as may be included in the header of FIG. 6 and whichincludes an energy director extending from an outer surface of theheader;

FIG. 12 is a detailed cross-sectional view of an alternative couplingarrangement between the retainer and header of FIG. 6 in which an energydirector of the retainer is received within a groove of the header;

FIG. 13 is a bottom plan view of another alternative retainer for use inthe septum assembly of FIG. 6, the alternative retainer including bothradially and circumferentially extending energy directors;

FIG. 14 is a detailed cross-sectional view of another alternativecoupling arrangement between the retainer and header of FIG. 6 in whicha sealing element is disposed between the retainer and the header body;

FIG. 15 is a detailed cross-sectional view of an alternative embodimentof the header assembly in which the retainer is received within acounter bore of the header body and the septum provides a sealingelement;

FIG. 16 is a detailed cross-sectional view of another alternativeembodiment of the header assembly in which the retainer is receivedwithin a counter bore of the header body;

FIG. 17 is a flow chart illustrating a method of assembling a header ofan implantable medical device including ultrasonically welded septumassemblies;

FIG. 18 is a cross-sectional view of an header including laser-weldedseptum assemblies;

FIG. 19 is an isometric cross-sectional view of a retainer of the septumassembly of FIG. 18;

FIG. 20 is a detailed cross-sectional view of the septum assembly ofFIG. 18;

FIG. 21A-21D are detailed cross-sectional views of the septum assemblyof FIG. 18 at different stages of manufacturing the septum assembly;

FIG. 22 is a flow chart illustrating a method of assembling a header ofan implantable medical device including ultrasonically welded septumassemblies; and

FIG. 23 is a detailed cross-sectional view of an alternative embodimentof a header assembly in which a retainer is received within a counterbore of the header body and the septum provides a sealing element.

DETAILED DESCRIPTION

Implementations of the present disclosure involve an implantableelectronic device (IED) such as an implantable pulse generator (IPG).The IPG administers electrotherapy or other neurostimulation via animplantable lead having a lead connector end on a proximal end of theimplantable lead. The IPG includes a housing or can and a connectorassembly enclosed in a header to form a header connector assembly thatis coupled to the housing or can. The header connector assembly has atleast one lead connector receiving bore or receptacle that includeselectrical contacts of the connector assembly that make electricalcontact with corresponding electrical terminals on the lead connectorend on the proximal end of the implantable lead when the lead connectorend is plugged into or otherwise received in the lead connectorreceiving bore or receptacle. Via the electrical connection between thecorresponding electrical terminals of the lead connector end and theelectrical contacts of the lead connector receiving bore, electricalsignals can be administered from the IPG and through the lead to patienttissue. Similarly, but in reverse, electrical signals originating inpatient tissue can travel via the lead to the IPG to be sensed at theIPG.

Setscrews may be used in the headers to secure leads in place withincorresponding lead bores or connector blocks. To facilitate access tothe setscrews, implantable medical devices in accordance with thepresent disclosure include septum assemblies disposed within a headerbody of the header. Each septum assembly includes a retainer that iscoupled to the header body when the header is assembled and a septumthat permits access to the setscrews using a torque driver or othertool. When the tool is not present, the septum provides a seal, therebypreventing ingress of electrical signals and bodily or other fluid intothe internal cavity of the header body. The retainer couples to theheader body to keep the septum at least partially disposed within theheader body.

In implementations of the present disclosure, the retainer of the septumassembly is configured to be welded to the header body, such as byultrasonic or laser welding. To do so, each of the header body and theretainer is at least partially formed from an weldable material, such asthermoplastic polyether polyurethane. Each of the retainer and headerbody may further include specific surfaces adapted to facilitate weldingof the two components. For example, in one implementation, the retainerincludes a flange that abuts the outer surface of the header body whenthe septum assembly is inserted into a septum assembly bore of theheader body. The retainer is then coupled to the header body by weldingthe abutting surfaces of the flange and header body.

In other implementations, other surfaces of the retainer and header bodymay be joined by the welding process. For example, in at least oneimplementation the septum bore of the header body includes a counterbore within which the retainer is seated such that a surface of theretainer abuts the bottom of the counter bore. The retainer is thenwelded to the bottom of the counter bore.

As further described below, in implementations involving ultrasonicwelding, the header body and/or the retainer may include one or moreenergy directors to facilitate welding of the two components. Ingeneral, an energy director is a protrusion or series of protrusionsthat form the initial contact between the two components. During theultrasonic welding process, the energy director focuses the appliedultrasonic energy, melting the energy director to form a joint betweenthe two components. Accordingly, implementations of the currentdisclosure include various arrangements of energy directors tofacilitate joining of the retainer and header body at various locations.

The foregoing and other features of the present disclosure regardingimplementation of the septum assemblies are provided below in furtherdetail. However, for purposes of context, a general overview of leadconnectors, IPG devices and IPG device headers is provided. It should benoted that the following overview is provided primarily for context andshould not be viewed as limiting the present disclosure to applicationsinvolving any of the specific example IPG devices discussed.

A. Overview of Lead Connector End and IPG

FIG. 1 shows a proximal end portion 10 of a transvenous, bipolar pacinglead, but is generally representative of any type of implantable leadwhether in the cardiac, pain management or other medical treatmentspace. The diameter of such a lead may be made a sufficiently smalldiameter to facilitate the lead's implantation into small veins such asthose found in the coronary sinus region of the heart and to allowimplantation of a plurality of leads into a single vessel for multi-siteor multi-chamber pacing. It should be understood, however, that otherlead designs may be used, for example, multipolar leads have proximalends portions that are bifurcated, trifurcated or have other branchedconfigurations. While the lead whose proximal end is shown in FIG. 1 isof the bipolar variety, there are unipolar leads that carry but a singleelectrode, and multipolar leads that have more than two electrodes.

As is well known in the art, bipolar coaxial leads typically consist ofa tubular housing of a biocompatible, biostable insulating materialcontaining an inner multifilar conductor coil that is surrounded by aninner insulating tube. The inner conductor coil is connected to a tipelectrode on the distal end of the lead. The inner insulating tube issurrounded by a separate, outer multifilar conductor coil that is alsoenclosed within the tubular housing. The outer conductor coil isconnected to an anodal ring electrode along the distal end portion ofthe lead. The inner insulation is intended to electrically isolate thetwo conductor coils preventing any internal electrical short circuit,while the housing protects the entire lead from the intrusion of bodyfluids. These insulating materials are typically either silicone rubberor polyurethane elastomers. More recently, there have been introducedbipolar leads in which multifilar cable conductors contained withinmultilumen housings are substituted for the conductor coils in order toreduce even further the overall diameter of the lead.

The proximal lead end portion 10 shown in FIG. 1 includes a leadconnector end 11 that conforms to the IS-1 standard, including a pair ofcoaxial spaced-apart electrical terminals including a tip terminal 12and a ring terminal 14. The tip terminal 12 is electrically connectedvia of the inner conductor coil to the tip electrode at the distal endof the lead, while the ring terminal 14 is electrically connected to theanodal ring electrode via of the outer conductor coil. The tip and ringterminals of the lead connector end may each be engaged by a conductivegarter spring contact or other resilient electrical contact element in acorresponding lead connector receiving bore of the header, the resilientelectrical contact element being carried by a connector assemblyenclosed in the header as described below. The lead connector end 11 onthe proximal lead end portion 10 further comprises spaced-apart pairs ofseal rings 16 for abutting against in a fluid-sealing manner the innercircumferential surface of the lead connector receiving bore of theheader, thereby preventing body fluids from reaching the electricalterminals and contacts when the lead connector end 11 is plugged intothe corresponding lead connector receiving bore. With the lead connectorend 11 of the lead inserted in the lead connector receiving bore of theheader and connector assembly, the tip and ring terminals 12 and 14 areelectrically coupled via the contacts of the connector assembly and afeedthru to the electronic circuits within the hermetically sealedhousing of the IPG (e.g., cardiac pacemaker, ICD, or other implantabletissue stimulation and/or sensing device such as those used in painmanagement, etc.).

FIG. 2 shows a multi-site or multi-chamber cardiacpacemaker/defibrillator unit that is generally representative of anytype of IPG 20 incorporating a header connector assembly 22 coupled to ahousing 24. The header connector assembly 22 includes a header 40enclosing a connector assembly 42, both of which are depictedrespectively in FIGS. 3, 4A and 4B discussed below. The IPG 20 includesa hermetically sealed housing 24, which is also known as a can orcasing. The housing 24 encloses the electronic components of the IPG 20with the header connector assembly 22 mounted along a top surface 26 ofthe housing 24.

FIG. 2 illustrates that, in some embodiments, the header connectorassembly 22 may include four or more lead connector receiving bores orreceptacles 30, 31, 32 and 33 for receiving the lead connector ends offour implantable leads. FIG. 2 also shows the proximal end portion 10 ofa lead, wherein the lead connector end on the proximal end portion 10 ofthe lead is received in a corresponding receptacle 32. In otherembodiments, the header connector assembly 22 includes a single pair ofreceptacles (i.e., receptacles 30 and 33) for receiving the proximalends of leads such as, for example, conventional bipolar leads and/orconventional cardioverting and/or defibrillating leads. One or moresetscrews 36 may be threadedly received in respective setscrew bores 34to secure the proximal end portion 10 of the lead in the headerconnector assembly 22, as discussed in greater detail below.

FIG. 3 is an isometric view of a representative header 40, and FIGS. 4Aand 4B are opposite isometric views of a representative connectorassembly 42. Unlike the header connector assembly 22 of FIG. 2, theheader 40 of FIG. 3 only has a single pair of receptacles 30 and 33.However, in other embodiments, the header 40 of FIG. 3 may have anysuitable number of receptacles including, but not limited to, two ormore pairs similar to the embodiment of FIG. 2.

Each receptacle 30, 33 is adapted to receive a proximal end of a lead,such as the proximal end portion 10 illustrated in FIG. 1. As shown inFIG. 3, the header 40 further defines a pair of setscrew bores 34, 35corresponding to the receptacles 30, 33, respectively. Correspondingsetscrews 36, 37 are disposed within the setscrew holes 34, 35 such thatwhen proximal lead ends are fully inserted into the receptacles 30, 33,the setscrews 36, 37 may be tightened to retain the proximal lead endswithin the header 40. For clarity and context, FIG. 3 omits septums fromthe header 40, however, when the header 40 is fully assembled, septumsare disposed within the setscrew bores 34, 35. An example of anassembled header with septums included is described below in the contextof FIG. 5.

As illustrated in FIGS. 4A and 4B, the connector assembly 42 includestip blocks 44 and ring blocks 46. The ring blocks 46 include springcontacts 48. Each electrical block 44 and 46 of the connector assembly42 serves as an electrical contact of the connector assembly 42. Thus,as can be understood from FIGS. 1-4B, each tip block 44 is configured toreceive and make electrical contact with the tip terminal 12 of a leadconnector end 11 received in the corresponding receptacle 30, 33 of theheader 40. Similarly, each ring block 46 is configured to receive andmake electrical contact with the ring terminal 14 of a lead connectorend 11 received in the corresponding receptacle 30, 33 of the header 40.While the connector assembly 42 of FIGS. 4A and 4B is of an IS-1configuration, other configurations (e.g., IS-4, etc.) are used in otherembodiments. While the connector assembly 42 of FIGS. 4A and 4B onlydepicts two pairs of blocks 44, 46, in other embodiments where theheader includes more than a single pair of receptacles 30, 33 (e.g., twopairs of receptacles 30, 31, 32, 33 as indicated in FIG. 2), theconnector assembly 42 will have a four pairs of blocks 44, 46.

As shown in FIGS. 4A and 4B, the connector assembly 42 also includes ahost of electrically conductive components including an antenna 48, a RFanchor tab 50, a RF pin tab 52, an A-tip tab 54, an A-ring tab 56, aRV-ring tab 58, a RV-tip tab 60, and a ribbon carrier 62 and otherconductors 64 that extend between the various tabs and their respectiveelectrical contacts of the connector assembly or other componentsthereof. In other words, as can be understood from FIGS. 4A and 4B,electrical conductor elements (e.g., wires, traces, or other electricalconductors) 64 extend between the electrical blocks 44, 46 and therespective tabs 50, 52, 54, 56, 58 and 60. Also, such conductor elements64 may form the antenna 48 and the ribbon carrier 62.

The various tabs are welded to corresponding terminals extending fromcircuitry of the IPG 20 contained in the housing 24 of the IPG 20depicted in FIG. 2 when the header connector assembly 22 is joined withthe housing 24 to form the IPG 20. The connector assembly 42 ismanufactured of materials and via methods known in the industry. Theconnector assembly 42 is cast in place, injected molded or otherwiseinstalled into the header 40 to form the header connector assembly 22 ofFIG. 2, which can be considered a first module that is then attached viaa backfill or other process to a second module in the form of thehousing 24. In other words, the header connector assembly 22 (i.e.,first module) is attached via a backfill or other process to the housing24 (i.e., the second module) to form the IPG 20.

The foregoing discussion is intended merely to provide context for thecurrent disclosure. Accordingly, any specific configurations or devicesdiscussed above or illustrated in the corresponding figures should beregarded merely as illustrating non-limiting implementations of thepresent disclosure. More generally, the current disclosure is applicableto any implantable medical device for which access to at least a portionof the device is facilitated by a septum or similar sealing mechanism.Accordingly, the current disclosure should not be regarded as beinglimited to ICD/IPG devices or any of the specific example devicesdescribed herein or their respective features. For example, devices inaccordance with the present disclosure may include any suitable numberof septums for accessing internal portions of the device which may bearranged in any suitable configuration. Moreover, while the currentdisclosure refers generally to septums used to access set screws, theseptums described herein may be used to access any internal component orvolume of an implantable device header.

B. Header Assemblies Including Ultrasonically Welded Septum Assemblies

FIG. 5 is a partial cross-sectional view of a header assembly 500 inaccordance with the present disclosure. As illustrated, the headerassembly 500 includes a header body 502 within which a pair of tipblocks 504, 506 is disposed. As previously discussed, the tip blocks504, 506 are configured to receive a lead tip, such as the tip terminal12 of the connector end 11 illustrated in FIG. 1.

To facilitate retention of the lead tips when received within the tipblocks 504, 506, the header body 502 defines septum bores 508, 510within which set screws 512, 514 and septum assemblies 516, 518 may bedisposed. As illustrated in FIG. 5, the septum bores 508, 510 may extendperpendicular to connector bores 520, 522 such that the set screws 514,516 are disposed adjacent to connector tip receiving bores 524, 526 ofthe tip blocks 504, 506.

When a tip terminal is received within one of the tip blocks 504, 506the respective set screw 512, 514 may be screwed further into the tipblock 504, 506 such that the set screw 512, 514 contacts and interfereswith the tip terminal, thereby retaining the tip terminal within the tipblock 504, 506. If the connector is to be removed, the set screw 512,514 may be counter-rotated or unscrewed such that the tip terminal maybe pulled out of the tip block 504, 506.

The septum assemblies 516, 518 are configured to enable insertion of atool for rotating and counter-rotating the set screws 512, 514 and toprovide a seal when the tool is not present. As illustrated in FIG. 5, afirst septum assembly 516 includes each of a first flexible septum 528and a first retainer 530 while a second septum assembly 518 includeseach of a second flexible septum 532 and a second retainer 534.

The following discussion focuses on the first septum assembly 516 andits various components and, as a result, refers to the first septumassembly 516 simply as the septum assembly 516, the first septum 528 asthe septum 528, and the first retainer 530 as the retainer 530. Itshould be understood that the following discussion regarding the firstseptum assembly 516 generally applies to the second septum assembly 518unless otherwise noted. While the header assembly 500 is illustrated inFIG. 5 and subsequent figures as including only two septum assemblies516, 518, it should be appreciated that in other implementations of thepresent disclosure, the header assembly 500 may include more or fewerset screws and, as a result, a corresponding number of septum assembliesmay be included. Moreover, while the current disclosure focusesprimarily on the use of the disclosed septum assemblies for purposes ofenabling ingress into the header assembly 500 of a tool for manipulatingthe set screws 512, 514, it should be further appreciated that thecurrent disclosure may be used in other applications or devices,including for other medical devices, in which access occasionally berequired into the device but that otherwise requires the device besealed.

Reference is now made to FIGS. 6-11, which provide additional detailsregarding the septum assembly 516. FIG. 6 is a detailed view of theseptum assembly 516 as disposed within the header body 502 of the headerassembly shown in FIG. 5; FIGS. 7 and 8 are isometric and isometriccross-sectional views of the septum assembly 516, respectively; and FIG.9 is a cross-sectional view of the retainer 530. For purposes of thefollowing discussion, like reference numbers are used to refer to thesame features or elements in each figure. Accordingly, to the extent areference number is indicated in a particular figure but not discussedin detail with respect to that figure, it should be understood togenerally correspond to similarly numbered elements in other figures.

As previously noted, the septum assembly 516 includes each of a septum528 and a retainer 530. The septum 528 is generally formed of a flexiblematerial, such as, but not limited to, silicone rubber. The septum 528may be split into two or more pieces or otherwise include a puncture orslit extending through the septum 528 to enable insertion of toolsthrough the septum 528. For example, in the implementation of FIG. 6,the septum 528 includes each of a first septum half 529A and a secondseptum half 529B. Also, as shown in FIG. 6, the septum 528 may include aguide surface 533 for directing tools toward the center of the septum528.

The retainer 530 of the septum assembly 516 retains the septum 528 andcouples the septum assembly to the header body 502. With respect toretaining the septum 528, the retainer 530 may include one or morechannels, grooves, or similar features that mate with correspondingfeatures of the septum 528 such that the septum 528 may be inserted intoand held within the retainer 530. For example, as shown in FIG. 6, theretainer 530 includes an inner circumferential groove 536 within whichan outer circumferential protrusion 538 of the assembled septum 528 isinserted. In implementations in which the septum 528 includes multiplepieces, the retainer 530 also servers to maintain the multiple pieces inproper relation to each other. The retainer 530 further defines a bore540 extending therethrough such that a tool may access the septum 528.

Coupling of the retainer 530 to the header body 502 may be achieved invarious ways; however, in general, the retainer 530 includes a featureor surface that abuts a corresponding surface or feature of the headerbody 502 when the septum assembly 516 is inserted into the septumassembly bore 508. Once inserted, the retainer 520 is joined to theheader body 502. In the following examples, such joining is accomplishedusing ultrasonic welding; however, as discussed later in thisdisclosure, other techniques, such as laser welding, may also be used.

In the specific example illustrated in FIG. 6 and FIG. 7, the retainer530 includes a flange 542 that extends radially outward from a body 544of the retainer 530. When the septum assembly 516 is disposed within theseptum assembly bore 508, the flange 542 extends beyond the septumassembly bore 508 and abuts an outer surface 503 of the header body 502.Once positioned within the septum assembly bore 508, a welding surface543 of the flange 542 may be joined to the outer surface 503 of theheader body 502, such as by ultrasonic welding. As a result of suchjoining, the septum assembly 516 is fixed to the header body 502 and theseptum 528 is retained in its proper location.

Although illustrated as being a unitary component, the header body 502may alternatively include a primary structure within which multipleinserts are disposed. The general location and extent of an example ofsuch an insert is indicated in FIG. 6 by dashed line 507. Asillustrated, the insert may generally replace a portion of the headerbody 502 of FIG. 6 that defines at least a portion of the septumassembly bore 508. Moreover, the insert may also provide the surface towhich the retainer 530 is welded. Among other things, the use of insertsprovides flexibility regarding material choice. More specifically, theinclusion of inserts formed from weldable materials, permits theremainder of the header body 502 to be formed from materials that, whileadvantageous for manufacturing or other reasons, may not be readilyweldable to the retainer 530. In certain implementations, the insert andthe header body 502 may be formed of a specific material amenable toultrasonic welding or other bonding with the retainer 530.

In certain implementations, joining of the septum assembly 516 to theheader body 502 may be facilitated by including one or more energydirectors or similar welding feature coupled to the retainer 530 or theheader body 502. In general, the welding feature is coupled to theretainer 530 or the header body 502 by being integrally formed with theretainer 530 or the header body 502; however, in other implementations,the welding feature may be a separate component that is attached to theretainer 530 or the header body 502. In general, an energy director is aprotrusion or similar feature that limits initial contact betweensurfaces being welded and focuses energy applied to the surfaces at oneor more apexes or similar terminal locations of the energy director.

For example, ultrasonic and similar welding processes are generallyperformed using a press-like machine. The components to be joined areloaded into the machine such that the surfaces to be joined are abuttingor otherwise aligned. In most cases, one component is disposed between arigid body (e.g., a nest, jig, or anvil) and the second component. Asonotrode is then translated to abut the second component and applypressure to the components while ultrasonic energy is provided to thesonotrode. The vibrations of the sonotrode are transmitted through thesecond component causing the abutting surfaces of the components to meltand the material of the two components to flow together, thereby bondingthe components. By implementing energy directors, the energy from thesonotrode can be directed to specific locations and can also lead tomore rapid bonding between the components due to the lower surface areaof the energy director as compared to the full surfaces of thecomponents.

As illustrated in FIGS. 8 and 9, the retainer 530 includes an energydirector 544 extending from the welding surface 543 of the flange 540.The energy director 544 is illustrated as a set of concentric triangularrings 546A-546C. Accordingly, when assembling the septum assembly 516 tothe header body 502, contact is first made between the outer surface 503of the header body 502 and the rings 546A-546C of the energy director544. As ultrasonic energy is provided to the retainer 530, theultrasonic energy is directed to the rings 546A-546C, causing them tomelt and join the retainer 530 to the header body 502. As shown in FIG.6, the result may be a weld bead or joint 548 formed between theretainer 530 and the header body 502.

The three-ring energy director of FIG. 9 is intended merely as anexample of energy directors that may be used in implementations of thepresent disclosure. FIG. 10, for example, is a cross-sectional view ofan alternative implementation of the retainer 530 in which theconcentric rings 546A-546C has been replaced by a single triangular ring550 extending circumferentially about the welding surface 543 of theflange 542.

The energy directors illustrated in FIGS. 9 and 10, which includetriangular protrusions extending from the flange 540 about the retainer530, are simply two examples of possible energy directing features thatmay be used in implementations of the present disclosure. In otherimplementations, one or both of the retainer 530 and the outer surface503 of the header body 502 may include other energy directorconfigurations.

For example, FIG. 11 is a cross-sectional view of a portion of theheader body 502 including the septum assembly bore 508 in which atriangular energy director 552 protrudes from the outer surface 503 ofthe header body 502 and extends circumferentially about the septumassembly bore 508.

As another example, FIG. 12 illustrates a tongue-and-grooveconfiguration in which the retainer 530 includes an energy director 544in the form of a tongue that is received within a corresponding groove546 defined in the outer surface 503 of the header body 502. In otherconfigurations, the tongue may instead extend from the outer surface 503of the header body 502 into a corresponding groove defined in the flange540 of the retainer 530.

Each of the configurations illustrated in FIGS. 9-12 generally includeenergy directors that extend continuously and circumferentially abouteither the flange 540 of the retainer 530 or the septum assembly bore508. In other implementations, however, such energy directors may bediscontinuous and/or extend, at least partially, in a radial direction.For example, FIG. 13 is a bottom view of the retainer 530 including bothpartial circumferential energy directors, such as energy director 560,and radial energy directors, such as energy director 562.

As previously noted, in certain implementations both the retainer 530and the outer surface 503 of the header body 502 may include respectiveenergy directors. Such energy directors may, in certain cases, cross orotherwise overlap. For example, radial energy directors of the flange540 may cross circumferential energy directors of the outer surface 503of the header body 502, or vice versa. In other implementations, one ormore energy directors of the flange 540 may be positioned on the flangeto extend between energy directors of the outer surface. In still otherimplementations, energy directors of the flange 540 may be disposed suchthat they do not intersect or interfere with energy directors of theouter surface 503. For example, the flange 540 may include a firstenergy director in the form of a ring having a first radius and theouter surface 503 may a second energy director in the form of a ringhaving a second radius different than the first radius.

In still other implementations, the retainer 530 and the outer surface503 may include additional structural features to facilitate theirjoining. For example, one or both of the retainer 530 and the outersurface 503 may include a surface that is at least partially textured orroughened. In such implementations, the raised portions of the roughenedsurface function similarly to the more prominent energy directorsdiscussed in previous examples.

The process of welding the retainer 530 to the header body 502 mayresult in a continuous joint or bead that provides a seal about thecircumference of the flange 540 or other interface between the retainer530 and the header body 502. However, a sealing element may also beincluded between the retainer 520 and the header body 502 to provide aprimary seal between the components or to provide a supplemental orbackup seal to the joint between the retainer 530 and the header body502. FIG. 14, for example, is a partial cross-sectional view of theseptum assembly 516 as installed in the header body 502. As illustratedin FIG. 14, a sealing element 564 in the form of an O-ring 564 isdisposed radially inward of the joint 566 formed between the retainer530 of the septum assembly 516 and the header body 502. To facilitateretention of the sealing element 564 one both of the retainer 530 andthe header body 502 may include a groove 565, cut-away, or similarstructural feature within which the sealing element 564 may be retained.Although illustrated in FIG. 14 as being disposed between the flange 540and the outer surface 503 of the header body 502, it should beappreciated that sealing elements may be at any suitable locationbetween the retainer 530 and the header body 502 so as to preventingress of bodily fluid into the inner volume of the header assembly.

FIG. 15 illustrates an alternative embodiment in which the header bodyincludes a counter bore 568 shaped to receive the retainer 530. As aresult, the retainer 530 may be at least partially disposed below theouter surface 503 of the header body 502. For example, in certainimplementations, the retainer 530 may be received within the counterbore 568 such that the retainer 530 is substantially flush with theouter surface 503. In such implementations, the retainer 530 may bewelded to a bottom 569 of the counter bore 568 as opposed to the outersurface 503 of the header body 502.

FIG. 15 further illustrates an alternative approach to forming a sealbetween the retainer 530 and the header body 502. In particular, theseptum 528 of the septum assembly 516 includes a septum flange 570 thatis disposed between the header body 502 and the retainer 530 when theretainer 530 is disposed within the counter bore 568. As pressure isapplied to the retainer 530 during the ultrasonic welding process, theseptum flange 570 is pinched between the retainer 530 and the headerbody 502, thereby forming a seal between the two components. It shouldbe appreciated that the specific sealing configuration illustrated inFIG. 15 is merely one example and other arrangements in which a flangeor other protrusion of the septum 528 is configured to extend betweenthe retainer 530 and header body 502 are also contemplated.

FIG. 16 is another example implementation of the header assembly 500 inwhich the retainer 530 of the septum assembly 516 is received such thata first portion 572 of the retainer is received within a counter bore568 of the header body 502, while a second portion 574 extends furtherinto the header body 502. In such implementations, the retainer 530 maybe ultrasonically welded or otherwise joined to the bottom 569 of thecounter bore 568. Similar to the implementation illustrated in FIG. 15,the retainer 530 is illustrated as being at least partially flush withthe outer surface 503 of the header body 502.

FIG. 17 is a flow chart illustrating an example method 1700 forassembling a header of an implantable electronic device (IED) and, morespecifically, for installing one or more septums within a header of theIED.

At operation 1702, an IED header is obtained. Although the presentdisclosure is applicable to various configurations of IEDs and IEDheaders, in general, the IED header includes at least one bore extendingfrom an outer surface of the IED header to an internal volume of the IEDheader. In at least some implementations, the bore may be used to accessset screws for retaining terminal ends of leads within the IED header.When obtained, the IED header may be a standalone assembly or mayalready be coupled to an IED housing (e.g., a “can” including electroniccomponents of the IED).

At operation 1704, a septum assembly is assembled. As previouslydiscussed in the context of FIGS. 7-10, the septum assembly generallyincludes a flexible septum retained by a rigid retainer, each of whichmay include multiple parts. In certain implementations, the retainer mayinclude channels, grooves, or similar structural features that mate withcorresponding structural features of the septum.

At operation 1706, the septum assembly is disposed in a bore of theheader. More specifically, the septum assembly is disposed within thebore of the header such that a surface of the retainer abuts a surfaceof the header and the septum is disposed within the header bore. Incertain implementations, the retainer may include energy directors inthe form of one or more protrusions, roughened surfaces, or similarstructural elements. In such implementations, disposing the septumassembly within the bore of the header generally includes positioningthe retainer such that the energy directors are made to contact asurface of the header.

In certain implementations, disposing the septum assembly in the bore ofthe header may further include placing a sealing element between theretainer and the header. As illustrated in FIG. 14, for example, anO-ring or similar sealing element may be disposed between the retainerof the septum assembly and the header. Alternatively, as illustrated inFIG. 15, a flange or similar portion of the septum may be configured toextend between the retainer and the header such that the septum providesa seal.

At operation 1708, the retainer of the septum assembly is ultrasonicallywelded to the header. To do so, a sonotrode (or similar tool fordelivering ultrasonic energy to the septum assembly) is pressed intocontact with the retainer of the septum assembly. With pressuremaintained on the sonotrode, ultrasonic energy is provided to thesonotrode and transferred to the retainer. Such energy causes at least aportion of the retainer (e.g., an energy director of the retainer) andan abutting portion of the header to melt and comingle such that whenthe ultrasonic energy is no longer provided to the sonotrode, thecomingled material cools to join the retainer and the header.

Following ultrasonic welding of the retainer to the header, installationof the septum assembly is substantially complete. The foregoing processfor installing a septum assembly may then be repeated for any number ofadditional bores of the IED header that may require a septum assembly.When properly installed, the septum of the septum assembly, the weldjoint formed between the retainer and the header, and any sealingelements disposed between the retainer, alone or in combination,effectively seal the IED bore such that fluid is prevented from enteringthe IED header through the bore. However, the septum generally permitsinsertion of elongate tools through the septum. For example, in oneimplementation, the septum may be adapted to permit insertion of atorque driver that may be used to tighten or loosen set screws disposedwithin the IED header.

C. Header Assemblies Including Laser-Welded Septum Assemblies

As noted above, coupling of a septum assembly to a header of the IED maybe conducted in various ways. For example, in the previously discussedimplementations of this disclosure, ultrasonic welding was implementedas the primary method for coupling a retainer of the septum assembly tothe header of the IED. In another implementation discussed in furtherdetail below, laser welding may instead be used to join a septumassembly to an IED header.

In one example implementation, the retainer of the septum assembly isdisposed within the IED header such that a surface of the retainer abutsa surface of the IED header. The retainer is generally formed from alaser-permeable thermoplastic material such that a laser may be passedthrough the retainer to weld the surface of the retainer to the surfaceof the IED header. In certain implementations, such welding is achievedwithout the need for adhesives, additives, or coatings applied to eitherthe retainer or header. However, in other implementations, additives orcoatings may nevertheless be applied to the retainer or header tofacilitate laser welding.

Although the particular laser used to weld the septum assembly to theIED header may vary, in at least one example implementation a two-micronfiber laser (such as a thulium nanosecond pulsed fiber laser) may beused. Such wavelengths generally correspond to lasers that exhibit goodpenetration into the thermoplastic material of the retainer to allowsub-surface clear-to-clear weld joining of the retainer to the IEDheader.

The foregoing and other aspects of the present disclosure are providedbelow in further detail. However, it should be appreciated that unlessotherwise specified, general aspects of IEDs, IED headers, and septumassemblies previously discussed in this disclosure generally apply toimplementations in which septum assemblies are laser-welded to IEDheaders.

FIG. 18 is a partial cross-sectional view of a header assembly 1800 inaccordance with the present disclosure. As illustrated, the headerassembly 1800 includes a header body 1802 within which a pair of tipblocks 1804, 1806 is disposed. The tip blocks 1804, 1806 are configuredto receive a lead tip, such as the tip terminal 12 of the connector end11 illustrated in FIG. 1. The header body 1802 defines septum bores1808, 1810 within which set screws 1812, 1814 and septum assemblies1816, 1818 may be disposed. The septum bores 1808, 1810 may extendperpendicular to connector bores 1820, 1822 such that the set screws1814, 1816 are disposed adjacent to connector tip receiving bores 1824,1826 of the tip blocks 1804, 1806.

The septum assemblies 1816, 1818 are configured to enable insertion of atool for rotating and counter-rotating the set screws 1812, 1814 and toprovide a seal when the tool is not present. More specifically, in theillustrated example, a first septum assembly 1816 includes each of afirst flexible septum 1828 and a first retainer 1830 while a secondseptum assembly 1818 includes each of a second flexible septum 1832 anda second retainer 1834. Reference in the following discussion is made tothe first septum assembly 1816; however, it should be understood thatdetails of the first septum assembly generally apply to the secondseptum assembly 1818 unless otherwise noted. The header assembly 1800may include more or fewer set screws than illustrated in FIG. 18 and, asa result, more or fewer septum assemblies.

Reference is now made to FIGS. 19 and 20, which provide additionaldetails regarding the septum assembly 1816. FIG. 19 is an isometriccross-sectional view of the septum assembly 1816 while FIG. 20 is adetailed view of the septum assembly 1816 as disposed within the headerbody 1802 of the header assembly shown in FIG. 18.

Similar to previously discussed implementations, the septum assembly1816 includes each of a septum 1828 and a retainer 1830. The septum 1828is generally formed of a flexible material and may be split into two ormore pieces (e.g., a first septum half 1829A and a second septum half1829B). The septum 1828 further includes a puncture or slit extendingthrough the septum 1828 to enable insertion of tools through the septum1828 and may include a guide surface 1833 for directing tools toward thecenter of the septum 1828.

The retainer 1830 of the septum assembly 1816 retains the septum 1828and couples the septum assembly to the header body 1802. With respect toretaining the septum 1828, the retainer 1830 may include channels,grooves, or similar features that mate with corresponding features ofthe septum 1828. For example, the retainer 1830 may include an innercircumferential groove 1836 within which an outer circumferentialprotrusion 1838 of the assembled septum 1828 is inserted. The retainer1830 further defines a bore 1840 extending therethrough such that a toolmay access the septum 1828.

In implementations of the present disclosure, the retainer 1830 iscoupled to the header body 1802 by laser welding a feature or surface ofthe retainer 1830 that abuts a corresponding surface or feature of theheader body 1802 when the septum assembly 1816 is inserted into theseptum assembly bore 1808. To facilitate such welding, each of theretainer 1830 and the header body 1802 may be formed from the sametransparent or translucent thermoplastic material. Alternatively, eachof the retainer 1830 and the header body 1802 may be formed of differentbut weldable materials. In one specific implementation, either or bothof the retainer 1830 and the header body 1802 may be formed fromthermoplastic polyether polyurethane, such as Elasthane™. Other examplethermoplastic polyether polyurethanes include, without limitationPellethane™ and Tecothane™. In other applications, the header body 1802and retainer 1830 may be formed of other materials, such as apolycarbonate urethane (e.g., Bionate™)

In the specific example illustrated in FIG. 19 and FIG. 20, the retainer1830 includes a flange 1842 that extends radially outward from a body1844 of the retainer 1830. When the septum assembly 1816 is disposedwithin the septum assembly bore 1808, the flange 1842 extends beyond theseptum assembly bore 1808 and abuts an outer surface 1803 of the headerbody 1802. When so positioned, a welding surface 1843 of the flange 1842may be joined to the outer surface 1803 of the header body 1802 by laserwelding, fixing the septum assembly 1816 to the header body 1802. Forexample, as illustrated in each of FIGS. 18 and 20, laser welding of theretainer 1830 to the header body 1802 generally results in a weld 1848formed at an interface between the retainer 1830 and the header body1802. In addition to joining the retainer 1830 and the header body 1802,the weld 1848 may also form a seal, preventing ingress of bodily fluidinto the header.

An example process for laser welding the septum assembly 1816 to theheader body 1802 is illustrated in FIGS. 21A-21D. The processillustrated in FIGS. 21A-21D is also summarized in the FIG. 22, which isa flow chart of a method 2200 of manufacturing an IED.

At operations 2202 and 2204, an IED header is obtained and the septumassembly 1816 is assembled (e.g., by inserting the septum 1828 into theretainer 1830). At operation 2206 and as illustrated in FIG. 21A, theseptum assembly 1816 is then disposed in the bore 1808 defined in theheader body 1802. More specifically, the septum assembly 1816 isdisposed within the bore 1808 such that the retainer 1830 abuts theheader body 1802 and the septum 1828 is disposed within the bore 1808.

At operation 2208 and as illustrated in FIG. 21B, pressure may beapplied to the retainer 1830 to improve contact between the retainer1830 and the header body 1802. In the example implementation illustratedin FIG. 21B, such pressure is applied by a plate 2102. The plate 2102may be formed of glass or another similar material that is substantiallytransparent to the welding laser such that the welding laser may passthrough the plate 2102 with minimal distortion, diffusion, attenuation,or other similar changes.

At operation 2210 and as illustrated in FIG. 21C, the retainer 1830 islaser-welded to the header body 1802 by a welding laser 2104. Ingeneral, the process of laser welding the retainer 1830 includesdirecting the welding laser 2104 through the retainer to an interfacebetween the retainer 1830 and the header body 1802. The welding laser2104 is directed along a path that extends about the retainer 1830 suchthat the welding laser 2104 heats material of each of the retainer 1830and the header body 1802, forming a weld/bead 1848 (shown in FIG. 21D)forms and joining the retainer 1830 to the header body 1802.

In one specific test of an implementation of the present disclosure,each of the header body 1802 and the retainer 1830 were formed fromElasthane™ and the welding laser 2104 was a two-micron thuliumnanosecond pulsed fiber laser. Although other laser settings arepossible, welding was conducted with a laser power of 75 W, a beam sizeof approximately 3.6 mm, and a focused spot diameter of 150 um. Thewelding laser 2104 was moved about the retainer 1830 at a linear scanspeed of approximately 150 mm/s and five passes were made about thecircumference of the retainer 1830. Based on the size of the retainer1830, the welding process lasted approximately 15 seconds and resultedin the weld 1848 being approximately 1 mm in width. During subsequenttesting, it was observed that such welding resulted in bonding betweenthe retainer 1830 and the header body 1802 that was approximately fourtimes greater than conventional adhesive/epoxy-based techniques.

As illustrated in FIG. 21D, when the weld 1848 is completed, the weldinglaser 2104 may be deactivated and the plate 2102 may be removed. Theforegoing process of inserting a septum assembly into a bore of theheader body and laser welding the retainer of the septum assembly to theheader body may then be repeated for any other septum assemblies to beinstalled.

IED headers including laser-welded septum assemblies in accordance withthe present disclosure may also incorporate features previouslydiscussed in the context of the ultrasonically welded septum assemblies.For example, similar to the implementation discussed in the context ofFIG. 6, the header may include an insert to which the septum assembly iswelded. In another example similar to implementations discussed in thecontext of FIGS. 15 and 16, the retainer of laser-welded septumassemblies may be disposed at least partially within a counter boredefined in the header body and welded to a bottom surface of the counterbore. As yet another example and similar to the implementationsdiscussed in the context of FIGS. 14 and 15, a seal element (e.g., anO-ring or a flange of the septum) may be disposed between the retainerand the header body to provide further protection from ingress of fluidinto the header. More generally, it should be appreciated that, with theexception of the septum assembly being laser welded versusultrasonically welded, aspects of the implementations discussed above inthe context of FIGS. 5-17 are generally applicable to implementations ofthe present disclosure including laser-welded septum assemblies.Accordingly and unless otherwise noted, any details or particulararrangements discussed in the context of ultrasonically weldedimplementations should be considered to equally apply to laser-weldedimplementations of the present disclosure.

In one specific example, FIG. 23 illustrates an alternative embodimentin which the header body 1802 includes a counter bore 1868 shaped toreceive the retainer 1830. As a result, the retainer 1830 may be atleast partially disposed below the outer surface 1803 of the header body1802. For example, in certain implementations, the retainer 1830 may bereceived within the counter bore 1868 such that the retainer 1830 issubstantially flush with the outer surface 1803. In suchimplementations, the retainer 1830 may be welded to a bottom 1869 of thecounter bore 1868 (as indicated by weld 1848) as opposed to the outersurface 1803 of the header body 1802.

The implementation of FIG. 23 further illustrates a seal between theretainer 1830 and the header body 1802 formed by a septum flange 1870 ofthe septum 1828. The septum flange 1870 is disposed between the headerbody 1802 and the retainer 1830 when the retainer 1830 is disposedwithin the counter bore 1868. As pressure is applied to the retainer1830 during the welding process (e.g., during operation 2208 of FIG.22), the septum flange 1870 is pinched between the retainer 1830 and theheader body 1802, thereby forming a seal.

The foregoing merely illustrates the principles of the presentdisclosure. Various modifications and alterations to the describedillustrative embodiments will be apparent to those skilled in the art inview of the teachings herein. It will thus be appreciated that thoseskilled in the art will be able to devise numerous systems, arrangementsand methods which, although not explicitly shown or described herein,embody the principles of the disclosure and are thus within the spiritand scope of the present disclosure. From the above description anddrawings, it will be understood by those of ordinary skill in the artthat the particular embodiments shown and described are for purposes ofillustrations only and are not intended to limit the scope of thepresent invention. References to details of particular embodiments arenot intended to limit the scope of the invention.

1.-40. (canceled)
 41. An implantable medical device within which a toolmay be at least partially inserted, the implantable medical devicecomprising: a header body comprising a first welding surface, the headerbody having an outer surface, an inner cavity, and a septum boreextending inwardly from the outer surface to the inner cavity; and aseptum assembly at least partially disposed within the septum bore, theseptum assembly comprising: a septum configured to allow insertion ofthe tool through the septum into the inner cavity and to provide a sealwhen the tool is not inserted through the septum; and a retainercomprising: a retainer body within which at least a portion of theseptum is retained; and a welding feature coupled to the retainer body,the welding feature comprising a second welding surface, wherein theretainer is coupled to the header body by the first welding surfacebeing welded to the second welding surface.
 42. The implantable medicaldevice of claim 41, wherein the welding feature is a flange extendinglaterally from the retainer body.
 43. The implantable medical device ofclaim 41, wherein the first welding surface is a portion of the outersurface.
 44. The implantable medical device of claim 41, wherein thefirst welding surface is disposed within the septum bore.
 45. Theimplantable medical device of claim 44, wherein the septum bore includesa counter bore and the first welding surface is at least a portion of abottom surface of the counter bore.
 46. The implantable medical deviceof claim 41, wherein each of the first welding surface and the secondwelding surface are formed from respective thermoplastic materials. 47.The implantable medical device of claim 46, wherein the respectivetransparent thermoplastic materials are each thermoplastic polyetherpolyurethane.
 48. The implantable medical device of claim 41, whereinthe header body further comprises an insert, the insert including thefirst welding surface and at least partially defining the septum bore.49. The implantable medical device of claim 41, wherein the septum isdisposed entirely below the outer surface of the header body.
 50. Theimplantable medical device of claim 41 further comprising a set screwdisposed within the inner cavity.
 51. The implantable medical device ofclaim 41 further comprising a sealing element disposed between theretainer and the header body, the sealing element providing a hermeticseal between the retainer and the header body.
 52. The implantablemedical device of claim 41, wherein the first welding surface is weldedto the second welding surface by laser welding.
 53. The implantablemedical device of claim 41, wherein the first welding surface is weldedto the second welding surface by ultrasonic welding.
 54. A method ofmanufacturing an implantable electronic device (IED), the methodcomprising: disposing a septum assembly in a bore of a header body ofthe IED, the septum assembly including a septum and a retainer, theseptum assembly disposed in the bore such that the septum is at leastpartially disposed within the bore and the retainer abuts a surface ofthe header body; and welding the retainer to the header body.
 55. Themethod of claim 54, wherein the retainer includes a body and a flangeextending from the body such that when the septum assembly is disposedin the bore, the flange abuts an outer surface of the header body andwelding the retainer to the header body comprises welding the flange tothe outer surface.
 56. The method of claim 54, wherein the bore includesa counter bore having a bottom surface and welding the retainer to theheader body comprises welding the retainer to the bottom surface of thecounter bore.
 57. The method of claim 54 further comprising, prior towelding the retainer to the header body, disposing a sealing elementbetween the retainer and the header body.
 58. The method of claim 57,wherein the sealing element is one of an elastomeric ring and a portionof the septum.
 59. The method of claim 54, wherein welding the retainerto the header body comprises laser welding the retainer to the headerbody.
 60. The method of claim 54, wherein welding the retainer to theheader body comprises ultrasonically welding the retainer to the headerbody.